-LRB- CNN -RRB- -- Before middle-aged men started singing `` Viva Viagra '' in TV ads , before former Sen. Bob Dole appeared in its commercials in the '90s , before the blue pill with a funny name entered the public lexicon , impotence was hush-hush .

Viagra entered the market 10 years ago , bringing once taboo subjects like erectile dysfunction out in the open .

Now there 's no getting away from it .

In-boxes are clogged daily with spam mail promising cheap and instant manliness delivered fast and in bulk . Couples exchange amorous , come-hither looks followed by a lengthy recitation of side effects on TV ads . The pill helped more than 25 million men get their groove back and blasted the topic of erectile dysfunction into the open .

`` It 's like the nuclear explosion , '' said Dr. Irwin Goldstein , director of Sexual Medicine at Alvarado Hospital in San Diego , California . `` It created sexual medicine . It allowed the taboo to be broken . ''

Since the diamond-shaped blue pill debuted 10 years ago , it has become embedded in the public psyche , late-night television jokes and urologists ' offices .

`` It is one of the revolutionary steps in sexual health , '' said Dr. Ira Sharlip , spokesman for the American Urological Association . `` It ranks with the changes in cultural attitudes about sexuality that were started by -LSB- Sigmund -RSB- Freud , continued by -LSB- William -RSB- Masters and -LSB- Virginia -RSB- Johnson , the two researchers in the '60s , and the work that -LSB- Alfred -RSB- Kinsey did in the '40s .

`` These were the huge steps in the development of our understanding of human sexuality and cultural attitudes of sex . ''

Men seldom talked about their bedroom troubles before the U.S. Food and Drug Administration approved Viagra as the first oral medication for erectile dysfunction in 1998 .

`` We lamented the fact that the men had so much shame about erectile dysfunction , how rarely anyone came for medical attention , '' said Dr. Abraham Morgentaler , an associate clinical professor of urology at Harvard Medical School .

Penis injections and vacuum pumps were available , but these treatments were n't appealing . Men with medical conditions such as diabetes , prostate cancer , hyper cholesterol , endocrinological and cardiovascular problems were n't able to enjoy sex , Goldstein said .

`` People who could n't enjoy intimacy before have been given a second life ... '' he said . `` We have had a better life because of it . ''

Viagra increases blood flow to the penis , enabling a man to have an erection . The drug does not induce desire and works when the man is sexually aroused , according to Pfizer , the makers of Viagra .

Urologists heard from patients who had tried the pill that Viagra made them feel as if they were 20-year-olds again . Anti-impotence drugs Levitra and Cialis have come along since .

`` Along with the birth control pill in the '60s , this pill really changed people , society and medicine , '' Goldstein said . `` It changed the patient-physician relationship . You can walk in and ask about sexual functions . It was a major taboo at some point . ''

Dr. Gerald Melchiode , a Texas psychiatrist , agreed that the pill has helped men open up about their sexual health , but finds the commercials a bit much .

`` I 've never run across men singing about their impotency , '' he said .

Since Viagra 's appearance on the market , the dialogue about sexual dysfunctions has helped doctors identify other health problems in their patients , doctors say .

`` You always hear someone drops dead , `` said Dr. Chris Steidle , a urologist who wrote the book `` Sex and the Heart . '' `` It 's not sudden death if you could n't get an erection . It 's a symptom of a heart condition . You would n't ignore a stroke , but you would ignore erectile dysfunction -- it 's a significant symptom . ''

The man 's penis is like `` the tip of the iceberg '' or `` the canary in the mines , '' which serve as an indicator of overall health , Morgentaler said .

`` There 's now good evidence that shows that men with ED who have no other symptoms of anything are at increased risk for heart attacks and strokes , '' he said .

Thousands of studies have been conducted on Viagra . `` The pill that thrills '' is also being studied to see whether it gives athletes an edge in competition . It 's been studied to see whether it helps women with their sexual health . Despite the deluge of attention , Viagra does n't work for about 25 percent to 35 percent of men with erectile dysfunction .

For others , it has revitalized and strained marriages . Experts say Viagra gave a window into the psyche of men and women .

Some complain that sex should be spontaneous and that popping a pill ruins the romance . Eating food decreases the potency of Viagra , and some say the pill forces them to go on a schedule . Another complaint : Having to use Viagra makes a spouse or partner feel undesirable .

`` Sometimes their spouse personalizes it , '' said Melchiode . `` Why does he have to take this pill ? Are n't I attractive enough ? Are n't I sexy enough for him ? That 's not unusual for the partner . ''

Even when Viagra is effective , some men realize that it 's not the magic bullet that solves their problems with intimacy , doctors said . Only about half refill their prescription .

`` One has to think beyond just giving a pill to cure sexual problems , '' Melchiode said . `` A typical example is a couple where there 's been problems over the years and they ca n't deal with the problems on a verbal level , so they start withdrawing from one another . They build up a resentment and anger , they have trouble being close to one another and having sex with each other . Just giving them a pill is n't going to touch on all the problems of the resentment and anger . ''

Sex , it turns out , is part of a bigger web of relationship issues .

Morgentaler , author of `` The Viagra Myth , '' said : `` It 's unrealistic that there 's a pill that fixes all of these things . ''

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Viagra helped 25 million men with erectile dysfunction and bring awareness

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Blue pill considered a huge step in understanding human sexuality , cultural attitudes

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ED indicates other health issues and that blood vessels are n't working well

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Viagra is n't a cure-all , some sex problems are indicative of relationship problems